1. Field of the Invention
This invention relates to power management for integrated circuits, and more particularly relates to application specific integrated circuit (hereinafter "ASIC") devices requiring low standby power consumption.
2. Background of the Invention
Many applications utilize ASIC devices that are battery powered and therefore require low standby power consumption. In such applications, it is desired to have the ASIC device be capable of running at its highest speed only during periods when the device's functionality is required.
One method of controlling the power consumption of an integrated circuit (IC) is to adjust the body voltage (i.e., the voltage magnitude between body and source) applied to the transistors on the IC. Specifically, by increasing the body to source voltage, transistors will have a higher threshold voltage, consume less power, and provide lower performance. Accordingly, increased body to source voltage is suitable for integrated circuits in standby mode when low power consumption is desired over high performance. Alternatively, by lowering the body to source voltage, transistors will consume more power, have a lower threshold voltage and provide higher performance. Accordingly, decreased body voltage is suitable for integrated circuits during a normal operating mode, when the transistors are active.
Unfortunately, no known system has provided a mechanism that can take full advantage of this ability to switch devices between high and low power consumption. In particular, known systems fail to provide a good solution to determine which devices on the ASIC to switch between power consuming states, and when the devices should be switched.